Closed loop resource allocation

Abstract

Method and apparatus for performing transmission data rate allocation in a high speed wireless communications network. A macro control loop with the network of base stations on one side and all the subscriber stations on the other side. Subscriber station selects a rate based on the amount of data queued for transmission (100). Adjusts this rate based on the available power headroom of the subscriber station (102). This adjusted transmission rate is then adjusted again to account for protection of base stations in the candidate set of the subscriber station (104). This rate is then adjusted in accordance with busy tone signals indicative of the loading conditions of active set base stations of the subscriber station (108). The base stations react to these action by refreshing measurements of their instantaneous traffic load and providing feedback in the form of soft busy tones. The algorithm is named Closed Loop Resource Allocation.

Description

CLAIM OF PRIORITY UNDER 35 U.S.C. §120[0001]The present Application for Patent is a Continuation and claims priority to patent application Ser. No. 09 / 409,981, entitled “CLOSED LOOP RESOURCE ALLOCATION,” filed Sep. 30, 1999 now U.S. Pat. No. 6,563,810, now allowed, and assigned to the assignee hereof and hereby expressly incorporated by reference herein.BACKGROUND[0002]I. Field of the Invention[0003]The present invention relates to wireless communications. More particularly, the present invention relates to a novel and improved method and apparatus for determining the transmission data rates in a high speed wireless communication system.[0004]II. Description of the Related Art[0005]A modern day communication system is required to support a variety of applications. One such communication system is a code division multiple access (CDMA) system which conforms to the “TIA / EIA / IS-95 Subscriber station-Base Station Compatibility Standard for Dual-Mode Wideband Spread Spectrum Cellular Sys...

AI Technical Summary

Benefits of technology

[0021]It is another objective of the present invention to allow data rate allocation on a per-packet basis, to provide the flexibility that is necessary to provide efficient service to subscriber stations offering traffic with high burstiness.

[0022]It is another objective of the present invention to provide fairness in resource allocation among the subscriber stations by taking into account the average throughput in the recent past and the possible buffer overflow condition.

[0023]It is another objective of this invention to provide efficient reverse link medium access control without requiring any signaling in the backhaul, between base station transceivers and base station controllers, even when the subscriber station is in soft handoff. This is highly desirable because it makes resource allocation independent from the network architecture and the associated transmission and processing delays.

[0024]It is another objective of the present invention to minimize the necessary signaling on the air interface.

[0025]It is another objective of the present invention to avoid resource waste that occurs when the rate used by the subscriber station is smaller than the allocated rate. In fact, in closed loop resource allocation the allocated rate and the used rate are always coincident.

[0026]It is yet another objective of the present invention to provide soft multi-bit busy tones that indicate not only whether a base station is in an overload condition or not, but also provides some indication of the extent of its loading.

Problems solved by technology

A significant difference between voice services and data services is the fact that the former imposes stringent and fixed delay requirements.

In principle, information can be exchanged between the network and the subscribers, but this involves signaling over the air interface which implies a waste of resources and a delay in the decision making process.

A first problem is therefore to design a medium access control strategy for the reverse link that exploits in an optimal way the available information minimizing signaling messages.

Another fundamental problem is resource allocation for a subscriber station in soft handoff.

Yet another fundamental problem is protection of base stations that are not in soft handoff with a particular subscriber station, but that nevertheless are connected to that subscriber station through an electromagnetic link with path loss comparable to those measured in the active set.

The base stations do not have this information absent a significant amount of signaling, which is undesirable.

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